Automatic signal for motion picture projecting machines



y 1933- H. CRABTREE AUTOMATIC SIGNAL FOR MOTION PICTURE PROJECTING MACHINES Filed Febf 13, 1931 ATTORNEY 5 5 m WW m6 w Patented May 23, 1933 UNITED STATES IVORY H. CRAIBTREE, F OAKLAND, CALIFORNIA AUTOMATIC SIGNAL FOR MOTION PICTURE PROJECTING MACHINES Application filed February 13, 1931. Serial No. 515,487.

This invention relates to improvements in motion picture projection machines, and more particularly it relates to automatic signaling devices, for use in connection with the film storage reel of a motion picture ma proach of the end of the film, then, second.

to indicate the exact time for making a changeover from the operating machine to the idle machine. The desirability for the first signal being that it gives a warning in suflicient time that the arc of the idle machine may be closed and properly heated before the machine is started for projection.

There are signaling devices now in use made in accordance with my co-pending applications, Serial Numbers 196,514 and 899,-

949, where automatic signaling devices are used in connection with automatic changeover mechanism. These signals, however, are not of an audible character, but are of a character designed to close a circuit through a signal lamp and are used also in connection with automatic changeover systems which can not be acquired by some people because, of their cost. The present type of signal is more desirable in some instances because it is relatively inexpensive and may be used to great advantage where only the signaling system is desired.

More specifically stated, the object ofthe present invention is to provide an audible 40 signal producing means for motion picture machines and to embody this means in the film storage reel to be operated incident to the winding oif of predetermined amounts of the film from the reel; the device to include a gong, a spring actuating hammer for striking the gong, and a spring actuated trigger for actuating the hammer. The trigger, in this instance, is so arranged that normally it will be held set under spring tension by the winding of the film strip over it, but

will be released when the film is unwound therefrom to thereby actuate the hammer against the gong and sound the audible signal.

' Anotherobject isto counterbalance the reel to compensate for the added weight of the signal device.

Other objects of the invention reside in the various details of construction, and in the combination of parts, and in the mode of operation, as will hereinafter be described.

In accomplishing these and other objects of the invention, I have provided the improved details'of construction, the preferred forms of which are illustrated in the accompanying drawing, wherein Fig. 1 is a sideelevation of a film strip storage reel for picture projection machines, equipped with signaling means embodying the present invention.

Fig. 2 is an enlarged sectional detail taken substantially on the line 22 in Figure 1.

Fig. 3 is an inside view of the trigger frame. 1

Fig. 4 is a sectional detail on line 4.4 in Figure 2. r I a Referring more in detail to the drawing-.

1 designates, in its entirety, alfilm storage reel of a character generally employed in the usual types of picture projecting ma-' chines and from which the film strip is wound as the picture isshown. This reel comprises a hub portion 2 which mounts a drum 3. The'drum is provided with the usual opposite side frames 4 and 5 between which the film strip 6 is wound in superimposed layers. The hub 2 may revolve on a reel supporting shaft 7 as the film is wound from the reel.

As shown in Figure 1, there is a frame plate 10 fastened to the side frame 4 of the reel by screws or bolts 11, and this plate is the preferred mounting means for the triggers or latch devices of the signaling apparatus. As shown best in Figures '2 and 3, this frame 10 which lies substantially parallel with the frame l, is provicledvwith integral opposite side fiangeslEZ and l3lbetween which a pair of triggers 14 and 15 are pivotally mounted by pivot'pins 16 extended" therethrough near their ends; the triggers are so located and pivoted that they may be extended between successive windings of the film strip in the reel. Coiled springs 18-18, which have ends attached to flange 19 extended across the lower end of the plate 10, are also attached to the inner ends of the triggers 14 and 15 so that when the film strip is wound off the reel to an extent sufficient to uncover the trigger, the springs throw the triggers upwardly and outwardly against the frame plate 10 and their relatively short ends downwardly.

Mounted about the hub of the reel at one end, or inside of the reel, and inset within the'drum at one side, is a gong 20, and overlying this are hammers 21 and 22, which have the ends of their supporting shanks 23 pivotally mounted on a cross pin 24 that extends between'the supporting flanges of the trigger frame'below the flange 19. Small springs 25 wound on pin 24 engage the drum and shanks of the hammers to normally retain the hammers lifted free of the gong.

.Pivotally connected with the inner ends of the triggers l4 and 15 and extended inwardly therefrom through guide slots 26 formed in the frame plate 10, are plungers or pushers 27 and 28, having inwardly rounded end portions adapted respectively to engage the hammers to actuate them against the gong when the triggers are re leased and actuated. In using the reel so equipped with the signaling means, the film strip is wound on the drum portion of the reel in the usual manner. Near the inner end of the film strip, after it has been wound several times about the hub, one of the triggers is adjusted inwardly so that it may be held flatly between adjacent windings of the film strip. Several more windingsar'e then wound on to the reel and then the second trigger is placed between the windings of the film. The film thus holds the triggers in set position against the pull of the springs 18-18 and ready for sounding the signal when the film is being wound from the reel in the usual course of showing the picture. hen it is finally wound off the reel to an extent sulficient to releasethe outer trigger, the tension of the spring 19 pulling on the trigger, throws it outwardly. This movement actuates the plunger 27 inwardly, and the inner end of the plunger engages with the shank of the hammer 21 to cause the hammer to strike the gong, thereby giving the operator an audible signal designating that it is time that he strike the arc of the second machine, or stand in readiness for any other operation. At a predetermined interval following the release of the first trigger, the second trigger will be released in a similar manner,

and this likewise sounds the gong to indicate a that the end of the film has been reached and that it is proper time to start projection from the second machine.

While I have illustrated the signal devlce as comprising two triggers, it is readily apparent that one or more may be employed,

without vibration, Ihave attached a counterweight 35 to the hub at a point directly opposite the frame 10.

It is also desired that the-hub 2 be slightly flattened, as at 8'6 in Figures 1 and 4,

in order that there will be added space for the film and no bulge will be caused in the windings because of the insertion of the two triggers.

It is apparent that various changes in dewithout departing from the spirit of the invention, and therefore, it is not desired that the claims limit the construction only to the details fherein shown, but that they be given tails of construction might be employed an interpretation as broad as possible commensurate with the scope of the invention disclosed.

Having thus described my invention, what I claim as new therein and desire to secure f by Letters Patent, is:

1. In a film feed reel for motion picture machines, a signal device comprising a trigger adapted to be held set under tension between windings of the film strip on the reel, a gong, a yieldingly supported hammer m5 and means operable incident to release of the trigger by the film strip to actuate the hammer against the gong; said hammer being lifted from the port after it strikes.

2. In a film feed reel for motion picture machines, a hub portion, a gong mounted thereon, a hammer adjacent the gong, a yielding support for the hammer normally] holding it disengaged from the gong, a trig-' ger adapted to be held set under tension between windings of a film strip on the reel and to be released by the unwinding of the film therefrom, a push rod to be actuated gong by its yielding sup- 1 by the trigger, and a spring for actuating the trigger, when released, to actuate the push rod to move the hammer against the gong; said hammer being lifted from the gong by its support after it strikes.

3. In a film feed reel for motion picture" reel, hammers mounted yieldingly to engage the gong and push rods attached to the triggers to engage the hammers to actuate them against the gong incident to release of their corresponding trigger.

4. In a film feed reel for motion picture machines, a hub portion about which the film strip may be wound in the reel, a gong mounted about the hub, a trigger frame fixe to the side of the reel, a plurality of triggers pivotally supported by the frame and having end portions adapted to be extended between windings of the film strip, a plurality of pivotally mounted hammers adapted to engage the gong, springs associated with the hammers for yieldingly retainin them disengaged from the gong, push ro s pivotally connected with the triggers and having ends slidable in the frame and adapted, when the triggers are released from the film strip, to engage their respective hammers for sounding the gong; said gong, hammers, trigger frame, and triggers being permanently mounted on the reel.

5. In a film feed reel for motion picture machines, a signal device mounted on the reel and comprising an element adapted to be held set under tension and to be released incident to unwinding of the film to a predetermined extent to thereby actuate the signal and means mounted on the reel to counterbalance the said signal device.

6. A device as in claim 3 wherein a counter seat is mounted in the reel diametrically opposite the signaling device.

7. In a film feed reel for motion picture machines, a hub portion about which a film strip may be wound, a signal device comprising triggers adapted to be disposed between windings of the film and to be held under tension thereby and to be released incident to unwinding of the film therefrom to actuate the signal; said hub having a flattened portion directly below the triggers for the purpose set forth.

8. A film feed reel for motion picture machines comprising a hub portion and opposite side portions between which the film strip is wound; one of said side portions being ofiset inwardly about the hub, a gong mounted about the hub within said inwardly offset portion and film controlled gong striking means mounted on the reel.

9. A device as in claim 8 wherein a signaling means is mounted by the side wall adjacent the gong including a hammer for a trigger member releasable incident to unwinding of the film strip to actuate the hammer against the gong.

Signed at Toppenish, Washington, this 5th day of February 1931.

IVORY H. CRABTREE. 

